In wireless communication, distortion occurs depending on the frequency of the signal when a baseband signal as a transmission signal is up-converted into a high-frequency signal and a high-frequency signal as a reception signal is down-converted into a baseband signal. For example, a frequency characteristics correcting device disclosed in Patent document 1 is known as a device for correcting signal distortion.
In the frequency characteristics correcting device of Patent document 1, in signal transmission by a transmission system circuit, part of a transmission signal is extracted by a coupling circuit and divided into a low-frequency portion and a high-frequency portion by respective band division filters and outputs (power levels) of the respective filters are detected by respective power detectors. Furthermore, in the frequency characteristics correcting device, a variable equalizer circuit is controlled on the basis of a voltage that is obtained by comparing outputs of the respective power detectors by a comparison circuit.